Geomagnetic Storms:Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm

Updated at: 2011 Sep 27 2210 UTC

Mid-latitudes

0-24 hr

24-48 hr

ACTIVE

15 %

05 %

MINOR

01 %

01 %

SEVERE

01 %

01 %

High latitudes

0-24 hr

24-48 hr

ACTIVE

20 %

05 %

MINOR

05 %

01 %

SEVERE

01 %

01 %

Tuesday, Sep. 27, 2011

What's up in space

Are we alone? Your iPhone has the answer. Download the all-new Drake Equation app to calculate the population of the Milky Way.

UARS RE-ENTRY ZONE: NASA has released a new statement pinpointing the re-entry of the UARS satellite on Sept. 24th: "The Joint Space Operations Center at Vandenberg Air Force Base in California has determined the satellite entered the atmosphere over the Pacific Ocean at 14.1 degrees south latitude and 189.8 degrees east longitude . This location is over a broad, remote ocean area in the Southern Hemisphere, far from any major land mass. The debris field is located between 300 miles and 800 miles downrange, or generally northeast of the re-entry point. NASA is not aware of any possible debris sightings from this geographic area." [more]

SUBSIDING STORM: A severe geomagnetic storm (Kp=7 to 8) that began yesterday when a CME hit Earth's magnetic field is subsiding. At the peak of the disturbance, auroras were sighted around bothpoles and in more than six US states including Michigan, New York, South Dakota, Maine, Massachusetts and Minnesota:

"The evening started off beautifully here in northeast Minnesota," says Travis Novitsky, who photographed the display from Grand Portage. "Almost as soon as it was dark we were seeing tall columns of green and red light. It was brief, yet spectacular!"

Sky watchers at the highest latitudes should remain alert for auroras as Earth's magnetic field continues to reverberate from the CME impact. Aurora alerts:text, voice.

BIG SUNSPOT: The source of all this solar and geomagnetic activity is sunspot AR1302. Measuring more than 150,000 km from end to end, the sprawling active region is visible even without a solar telescope. Fabiano Belisário Diniz saw it plainly in last night's sunset from Curitiba, Brazil:

"It was overcast and cold all day long, but at the end of the day a break in the clouds revealed the sun and AR1302," says Diniz. "What a great sight!"

The sunspot has quieted down since unleashing dual X-flares on Sept. 22nd and 24th. Nevertheless, NOAA forecasters estimate a 40% chance of more X-flares during the next 24 hours. Any such eruptions would be Earth-directed as the sunspot crosses the center of the solar disk. Solar flare alerts:text, voice.

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.

On September 27, 2011 there were 1250 potentially hazardous asteroids.